Toward the Targeted Material Removal with Optimized Surface Finish During EDM for the Repair Applications in Dies and Molds

The importance of dies and molds in the manufacturing industry cannot be mitigated, but their frequent and ongoing use frequently necessitates repair as their surface wear is associated with repetitive applications. Among the distinct machining options available in this regard, Electric discharge machining (EDM) is a promising candidate. However, the inherent stochastic nature of the process makes specific control challenging because there occurs a significant difference between designed and actual MRR which severely hinders the targeted material removal. Thus, the application of EDM in getting controlled MRR with minimum surface roughness (SR) for repair purposes is not yet significantly explored. Also, the selection of the most suitable electrode material from three different material categories (metal, non-metal, ceramic) in controlled machining has still not been explicitly discussed before. The experimentation was performed by following Taguchi L18 orthogonal array with six EDM variables along with relative MRR and SR as output responses. The findings revealed that the relative MRR (103%) was close to the desired MRR (100%), with a minimal surface roughness-SR (2.48 µm). The machining performance of three electrodes concerning the controlled machining with minimum surface roughness followed as Tungsten carbide (WC) < Copper (Cu) < Graphite (C). This work will be helpful for the repairing of the dies and molds engaged in aerospace applications.